package com.cwz.gateway.handler;

import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.cwz.core.utils.servle.ServletUtils;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebExceptionHandler;
import reactor.core.publisher.Mono;

/**
 * @program: w-demo
 * @description: Sentinel 自定义限流异常处理
 * @author: Wen
 **/
public class SentinelFallbackHandler implements WebExceptionHandler {
	@Override
	public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {
		if (exchange.getResponse().isCommitted()) {
			return Mono.error(ex);
		}
		if (!BlockException.isBlockException(ex)) {
			return Mono.error(ex);
		}
		return handleBlockedRequest(exchange, ex).flatMap(response -> writeResponse(response, exchange));

	}

	private Mono<Void> writeResponse(ServerResponse response, ServerWebExchange exchange) {
		return ServletUtils.webFluxResponseWriter(exchange.getResponse(), "请求超过最大数，请稍候再试");
	}

	private Mono<ServerResponse> handleBlockedRequest(ServerWebExchange exchange, Throwable throwable) {
		return GatewayCallbackManager.getBlockHandler().handleRequest(exchange, throwable);
	}
}
